Brain tissue damage, resulting either from injuries or disorders (e.g., neurodegenerative and cerebrovascular diseases), are a leading cause of long-term disability. Due to their pluripotency, embryonic stem cells (ES cells) hold a great promise for treating brain tissue damage (Lindvall et al., 2004, Nat. Med., 10 Suppl:S42-50; and Taguchi et al., 2004, J. Clin. Invest.; 114(3):330-338). However, ethical and logistical considerations have hampered their use (Barinaga, 2000, Science, 287(5457):1421-1422; and Boer, 1994, J. Neurol., 242(1):1-13). There is a need for an alternative to ES cells in treating brain tissue damage.